Magnum Venus Plastech Turbo Autosprue -TAS - Manual (Page 3)

Turbo Autosprue Instructions Issue_ 11 17/12/08 Magnum Venus Plastech Ltd - Reg No 3978164 Page 3 of 6
Maintenance:
(Refer to drawing 22414 below)
The Turbo Autosprue™ is designed to operate for several hundred injection cycles without any need for
maintenance. After lengthy service (700-1200 cycles) we recommend that the following maintenance
checks are carried out.
1. TESTING THE SEALS.
Operate the valve between open and closed and check that the valve nose seal moves back and forward
by 7- 8mm. If the movement of the nose seal is observed to be sluggish proceed to check, and if
necessary replace, the main piston seal and / or the shaft seals.
2. CHANGING THE NOSE SEAL.
With the TAS closed (no open signal) operate the machine
’s flush cycle.
After 12 seconds and with the air-dry flush cycle still operating block the drain pipe outlet. This will
pressurise the valve
’s fluid section and enable the observation of any air leakage out through the main
nose seal # 5837.
Should any air leakage be present under these conditions replace the nose seal # 5837.
The integrity of the nose seal # 5837 is determined entirely by the tightness of the nose screw # 5832 as
it compresses the nose seal against the washer # 6095 and the base of the shaft.

CORRECT TIGHTENING of the nose screw will seal the nose.

OVER TIGHTENING of the nose screw will seal the nose BUT prevent the nose seal moving back
and forth between the seal surface of the nose # 5852 and the seal surface of the body # 5831.

UNDER TIGHTENING of the nose screw will not seal the nose and it may leak solvent and air into the
mould cavity and/or leak resin through to the flush outlet whilst injecting.
To achieve the correct tightening of the nose screw we recommend the following actions:
Assemble the nose seal # 5837 with the back-up washer # 6059 and the nose seal screw # 5832 as
shown using a small amount of
BLUE LOCTITE 243 on the end of the screw. Screw into the shaft end #
5828 until it is finger tight and meets some resistance.
At this point proceed to turn the screw a further ¼ to ½ turn ensuring that the shaft # 5828 does not turn
at the same time. - To prevent the shaft from turning, apply 6
– 7 bar air pressure to the 4mm air fitting #
0645 on the side of the main body. This will open the valve and hold the shaft tight.
Immediately reassemble the valve and connect to the machine, and with the TAS out of the mould
operate the flush cycle and observe that there is no leak of solvent, or air from the sealed nose.
To test the integrity of the nose seal, further pressure can be applied to the TAS by blocking the TAS
drain pipe whilst the machine is flushing, this action will place the nose seal under full shop air pressure.
NOTE: The flush line should only be blocked in this manner once the solvent has flushed through and the
valve is only purging with air pressure.
If any leakage is observed at the nose during this test, immediately tighten screw # 5832 by a further ¼
turn, or more until the leak is sealed. This will increase the diameter of the nose seal # 5837 a further
fraction of a millimetre and effectively seal the nose in both the closed and open conditions.
3. CHANGING THE PISTON SEAL & SHAFT SEALS.
The 2 main shaft seals # 6004 should be replaced every 2,000 cycles or sooner if required. Any resin
found to be migrating into the upper air cylinder indicates the need for the immediate renewal of seals #
6004.
These are accessed by first removing the nose seal # 5837, then unscrew the cylinder top (but be aware
of the force of the internal spring). The Spring, Limiter and Piston assembly is then withdrawn from the
open cylinder end by pulling on the end of the brass shaft.
For further details of Turbo Autosprues required to operate at temperatures higher than 120ºC,or for use
at higher pressures, Contact your local Magnum Venus Plastech distributor.